When performing a HVAC reversing valve replacement

The valve is rated for a maximum working pressure of 15 psi for saturated steam and 60 psi for non-shock water applications

24L1801 is simply an older part numbering convention

This unit also features an integrated 1k ohm thin film nickel temperature sensor

Lochinvar & A.O. Smith 100109962 Switch 318820-201 When performing a HVAC reversingThe Lochinvar and A. O. Smith 100109962 Blower Prover Switch is a critical safety component designed to verify adequate airflow within the combustion chamber before ignition occurs. This differential pressure switch serves as the current OEM replacement part for legacy numbers 9004586215 and NS2 0097 00. When the inducer motor engages, this switch monitors the pressure drop across the venturi or heat exchanger, ensuring the system can safely vent flue